The present invention relates generally to components used in subterranean environments, and by way of example to submersible electric motors that are reused and/or serviced based at least on length of service.
This section is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Electric motors and other components are used in a variety of subterranean applications, such as electric submersible pumping systems. In one example, the submersible motor, along with the rest of the submersible pumping system, may be inserted into a wellbore and lowered until submerged in the desired oil and/or other fluids. The desired fluids collect in the wellbore, and are raised to a point above the earth""s surface via the submersible pumping system powered by the submersible motor.
A typical submersible motor, used to pump production fluids from beneath the earth""s surface, has an outer housing substantially sealed from the production fluid environment and sized to fit within standard wellbore casings. An exemplary submersible motor is a three-phase induction-type motor, having a shaft rotatably mounted within the housing such that it is in general alignment with the axis of the wellbore when residing in the wellbore.
Power may be supplied to the submersible electric motor via a power cable that runs along the deployment system. Typically, the power cable is banded or supported along either the outside or the inside of the deployment system. Generally, the power cable is routed to the electric motor to supply electric power thereto, and the submersible pump is powered by the motor by way of an appropriate drive shaft.
Periodically, the submersible motor, along with the rest of the submersible pumping system, must be removed from the well for movement to another well, for servicing, for replacement, etc. When servicing is required, the submersible motor is disconnected from the remainder of the submersible pumping system and shipped back to the factory or a servicing location. Disassembly of conventional motors sometimes requires the breaking or removal of weldments, making servicing difficult in a field environment. Of course, the cost and delay associated with shipping motors to a servicing center are undesirable. Servicing also can lead to downtime at the well which interrupts production of the petroleum or other wellbore fluid.
Attempts have been made to reduce downtime by providing accurate data regarding the service time of the motor. Such data can be useful in estimating remaining life of the motor, need for servicing, the parts that may be required for servicing, etc.
In some applications, external recording devices monitor the length of time a given system, e.g. a submersible pumping system, has been in service. However, the data does not apply to individual components, such as motors, once those components have been separated from the system or combined with another system. Additionally, external recording devices cannot capture previous component use. The external recording device only tracks time of use for the overall system once assembled.
Certain aspects commensurate in scope with the originally claimed invention are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.
The present invention provides an innovative approach to evaluating and servicing subterranean systems and components, such as electric motors. While the approach may be utilized in a variety of different fields and with different components and systems, an exemplary use is with electric motors used in, for example, submersible pumping systems. The technique incorporates a cyclic event monitor and recorder within the circuitry of a device, such as an electric motor.
The addition of a recording device within an electric motor limits service-reporting errors and decreases down time of the motor. Therefore, with an internal cyclic event monitor and recorder, the time to failure estimates and quality considerations stay within the confines of the product.